Fluid-ejection devices are used to eject fluid onto media and other surfaces. One common type of fluid-ejection device is an inkjet-printing device, such as an inkjet printer, which is used to eject ink onto media like paper to form images on the media. The component of the fluid-ejection device that actually ejects the fluid is a fluid-ejection assembly, which is commonly referred to as a printhead, such as an inkjet printhead in the case where the device is an inkjet-printing device. A fluid-ejection assembly is typically formed of at least two parts: a die that has a number of fluid-ejection nozzles through which the fluid is ejected as droplets, and a substrate affixed to the die to route the fluid to the die.